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such as industry, a university, or a non-profit, to collaborate on research and development projects in which the creation of intellectual property (inventions and data) is possible. CRADAs support technology transfer by spelling out in advance how intellectual property that is generated will be handled. Regardless of whether research results in an invention, CRADAs allow non-government partners to gain access to the unique technologies, facilities and expertise available at national labs. For example, through the R&D collaboration, the non-government partner may discover and license previously invented ORNL technologies or manufacturing techniques for integration into its products or processes. Or the partner may benefit from modeling guidance or experimental performance characterization during prototype development. Through CRADAs, science can be translated more quickly into products on the market, creating jobs and saving energy. Through the ORNL-Hillphoenix CRADA, ORNL researchers Brian Fricke and Vishaldeep Sharma worked on the team that tested the redesigned Advansor refrigeration system. Their primary goal was to ensure that the system emits 75% less greenhouse gas (from energy use and refrigerant leakage over service life), consumes 25% to 30% less energy than existing systems, and has refrigerant leak rates of less than 5% annually. In addition to the collaboration between Hillphoenix and ORNL, contributions made by industry partners Danfoss, Luvata and SWEP contributed greatly to the success of the project. It’s understandable that targeting commercial refrigeration for environmentally friendly alternatives is a priority for DOE and ORNL. There are approximately 35,000 supermarkets and over 150,000 convenience stores in the U.S. Traditional HFC-based multiplex direct expansion (DX) systems have large refrigerant inventories and high annual leakage rates. Refrigeration systems in supermarkets account for approximately 50% of their energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. High energy consumption equates to high greenhouse gas emissions, as does the high amount of refrigerant leakage. “Each supermarket has a lot of refrigerant in its system – two to four thousand pounds – and about 20 to 25% of that leaks out every year,” said Fricke.
Advansor transcritical CO2 compressor rack.
USING LCCP METHODOLOGY The research team performed analyses on a variety of supermarket refrigeration systems and refrigerant options, looking for a system configuration and refrigerant that reduced both energy consumption and life-cycle carbon-equivalent emissions. The team used the Life Cycle Climate Performance (LCCP) methodology to determine the environmental impact of a refrigeration system design during its service life. This methodology has become the international standard for such assessments. For energy consumption analyses, the team used DOE’s flagship modeling tool EnergyPlus to calculate the hourly energy consumption of the alternate refrigeration systems in different U.S. climate zones. The researchers evaluated standard- and highefficiency refrigerated display cases, walk-in coolers and freezers, and various refrigeration systems, including traditional multiplex DX rack systems, cascade systems with secondary loops, and transcritical CO2 systems. Their results demonstrated that a transcritical CO2 booster refrigeration system, coupled with high-efficiency display cases and walk-ins, can achieve energy reductions of up to 39% (depending on ambient temperature), compared to the standardefficiency R-404A multiplex DX system, with 76% lower emissions. These findings accompanied Hillphoenix's Second Nature Advansor System's birth into the North American market. Early this year, Hillphoenix introduced the AdvansorFlex CO2 refrigeration system, a smaller format version of the Advansor system. “While it’s not perfect, CO2 is only going to get more popular as time goes by,” Fricke said. ORNL has nearly 20 CRADAs in the works, including assessments of other refrigerants and systems that are targeted for market introduction within the next few years. MT Marlene Taylor is a technical writer at CSRA, a U.S. government contractor that provides IT and professional support. It is based in Falls Church, Virginia. September 2016 Accelerate America
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